1. Field of the Invention
The present invention relates to a clamping arrangement, especially for the clamping or gripping engagement of dental implements, including a receiving sleeve which is rotatably supported in a handpiece and is connected with a rotary drive, which includes at least one clamping element exerting a radially inwardly directed pressure against the shaft of the implement which is inserted into the receiving sleeve because of contact against an inclined track oriented perpendicular to the longitudinal axis of the clamping arrangement. The handpiece can pertain to a straight handpiece or to an angled handpiece (elbow) with an angled headpiece.
The invention is particularly adapted as a clamping arrangement for the clamping or gripping engagement of medical, and preferably dental implements.
2. Discussion of the Prior Art
A clamping arrangement of that type has become known from the disclosure of Swiss Pat. No. 581 463. In this known clamping arrangement, the clamping element is formed by a ball which is supported so as to be radially displaceable within a radial cutout in the receiving sleeve, and which can be clamped through the intermediary of the inclined track against the shaft of the implement, which must be inserted into the recieving sleeve prior thereto for the purpose of implementing the clamping. It is the purpose of the known clamping arrangement to allow for the clamping of such shafts of dental implements which are differingly constructed in diameter as well in configurations. Hereby, this relates to so-called instruments or implements, the shafts of which can possess extremely different shapes for increasing their gripping strength.
It has been shown in actual practice, that the above-described purpose can only be partly fulfilled with the known clamping configuration. This is based on a number of reasons.
An important reason is that, in the vast majority of instances, there is only obtained a point like or punctiform contact between the spherical clamping element and the shaft which is to be clamped. As a consequence, the clamping of the shaft is rendered considerably more difficult, inasmuch as there are necessitated relatively larger forces in order to clamp the implement in the receiving sleeve so as to be secured against rotation.
A further deficiency of the known configuration resides in that the clamping element, in the presence of reductions or contractions in the shaft of the implement, must carry out relatively extensive radial adjusting movements in order to be able to come into contact with the associated contour of the shaft. As a result thereof, not only are there prescribed relatively extensive movements for the inclined track, but there is also required a relatively large force in order to radially displace the clamping element. At a manual displacement of the inclined track, this leads to a significant amount of work.
A further disadvantage is associated with the abovedescribed deficiency and in which the spherical or ball-shaped clamping element, upon abutting against the inclined surfaces of the implement shaft, produces relatively high axial force components on the shaft, as a result of which there are necessarily also produced relatively high axial supporting forces between the shaft and the receiving sleeve. This deficiency is prescribed by the ratio in size between the clamping element and a cutout present in the shaft, which must be considered as being unsatisfactory. It must be noted herein that any elimination of the above-described deficiencies through an increase in the size of the spherical clamping element, especially for handpieces, is not possible, inasmuch as this would lead to an increase in the overall dimensions, which should be avoided for handpieces.